IL22 and asthma: Liu et al. showed that blood from asthmatic children containing high levels of IL-22 and IL-22-producing lymphocytes had the ability to stimulate embryonic fibroblast proliferation and production by fibroblasts of collagen (α-1 and α-2 chains of collagen 1), thus suggesting a contribution of IL-22 to subepithelial fibrosis in asthma through its action on fibroblasts.